Qualitative analysis of exercise or physical training has historically been based on three parameters: exercise duration, exercise frequency and exercise intensity. Measuring either of the first two parameters is well understood and relatively easy. Measuring the third parameter accurately has historically proven difficult, especially in modes of exercise that involve free body movement.
One method to estimate exercise intensity is through the use of wireless heart rate monitors. A chest strap that measures electrical conduction (EKG) of the heart transmits data to usually a watch type of receiver so that the current heart rate can be viewed during exercise. These have been widely available since the early 1980's and models range from simple monitors that only give current heart rate data to extremely complex monitors that combine GPS data and several data analysis software packages and systems. Although these devices are widely used and have been developed to provide almost every sort of heart rate data available, they are still only estimates of actual work rate during exercise. The heart rate is used as an estimator of the individual's current rate of work output but it is just that, an estimate and not an actual direct measurement of workload being done. The inherent problems of using heart rate to estimate exercise intensity (workload) are that the relationship between heart rate and work rate is not linear, the heart rate response varies between individuals, the heart rate response is affected by environmental factors such as temperature and humidity, the heart rate response is affected but current health status (dehydration, illness, etc.) and an individual's heart rate response varies with changes in fitness levels.
During the early 1980's elite level road cyclists began experimenting with what I believe is the direct measurement of work being done during exercise outside of a laboratory environment. Professionals began testing devices that used strain gauges in the crank to measure torque and with a concurrent angular velocity measurement, an actual power reading could be determined in watts and work being done could be calculated. Commercial versions of these power meters for bicycles became available in the late 1980's, and various models have since been developed. The main difference is where the strain is measured: the crank, the bottom bracket, the rear hub and the pedals are all locations of strain gauges that have been marketed. The advent of the commercially available power meter transformed higher level training; no longer was training volume and intensity being described as time spent in various heart rate zones (with all its inherent shortcomings), training was more accurately described by instantaneous wattage (intensity) and Joules of work (quantity) being done. This created the ability to measure and prescribe actual intensity and actual quantity or work done irrelevant of environmental conditions, change of fitness, equipment being used, etc. Individuals could be compared with absolute numbers and talent identification became much more concrete. Coaching and training became divided with the recreational masses still using heart rate due to the affordability and relatively simpler training analysis and prescriptions while the serious and elite athletes predominantly using direct power (wattage) and work (Joules) to measure, describe and prescribe training.
The development of the bicycle power meter and coaching using this device created markets for software (both web based and computer based) to analyze the data, online coaching services that could now have accurate qualitative and quantitative training data off site and an accurate way to prescribe training, and continued development of competing power measuring devices that created more affordable units. Units measuring things other than mechanical strain are also being developed (they measure the cyclist's opposing forces and combined with known velocity, produce a power measurement).
Compared to heart rate monitors, power meters are still relatively expensive so their market is still small compared to the market for heart rate monitors and their related products and services. Upstream users such as elite athletes, coaches, clinical professions and exercise physiologists understand the need for an actual direct measurement of work for accuracy and have been paying the cost differential since the inception of power meters. The rate at which technology, competition and development have expanded the choices while lowering the entry price in the cycling market points to widespread use in the near future, much like the expansion of heart rate monitors in general fitness.
The methods and apparatus that follow are designed to produce direct measurements of work being done in most exercise situations without the need for work being done on something, as in the bicycle power meter. The bicycle power meter has the advantage of the work is being put into a system that lends itself to measuring force, distance, angular velocity, etc. The measurement of work and power is much more complex with say, weight lifting as the direction of forces being applied, the lack of work being put into a closed system that lends itself to measurements, etc. creates a scenario much more complicated. Fortunately technology is advancing to make actual work measurements such as this and motion tracking and associated motion recognition and motion matching possible with the correct methodology.
Increasing awareness of health benefits derived from physical exercise and participation in athletic events has spawned an increase in the numbers of individuals engaged in these activities. Many individuals train or work out in clubs or indoor gyms using exercise equipment that include various sensors for measuring physical and/or physiological parameters associated with the user's workout. For example, treadmills, elliptical trainers, stair steppers, stationary bicycles, and the like often provide electronic devices that measure or estimate various physical and/or physiological parameters associated with a workout or training exercise, such as the distance traveled, the elapsed time of the exercise, the altitude climbed, the inclination level, the movement rate (e.g., miles per hour, etc.), the heart rate, the power expended, the calories burned, the rate of calories burned, etc. In some gyms or clubs, data relating to an individual's workout may be transmitted automatically from the exercise equipment directly to a computer system and stored. Athletes, their trainers, and/or their coaches may gain access to this data, e.g., for post-workout analysis, to gauge progress or improvement, to develop future workout routines or plans, etc.
Thus a need exists for a method and apparatus that provides a more effective means of computing total power output of a user performing free body exercises.